Place eggs in a saucepan large enough to hold them all in one layer.,Cover with water.,Bring to boil, then lower heat to a simmer and cook for 9 minutes.,Fill a large bowl halfway with ice and water.,When eggs have cooked, transfer them with a slotted spoon to ice bath.,Let cool completely.,Peel eggs; cut each in half lengthwise.,Remove yolks and place in a bowl.,Mash yolks with a fork until smooth.,Add mayonnaise, mustard, salt and pepper and mix until blended.,______,If using ziplock bag, seal bag and snip off one corner.,Pipe yolk mixture into empty egg whites.